Slurry Seal Assembly

ABSTRACT

A slurry seal assembly for use about a rotatable shaft between a process side and an atmosphere side is presented. The slurry seal assembly includes a sleeve, a rotatable seal ring, a stationary seal ring, a floating bushing seal assembly, and a plurality of slots. The sleeve is disposed about and rotatable with the shaft. The rotatable seal ring contacts and is rotatable with the sleeve. The stationary seal ring is arranged to form a sealing interface with the rotatable seal ring. The floating bushing seal assembly is disposed about the sleeve so that an inner annular surface along the floating bushing seal assembly is separated from an outer annular surface along the sleeve by a gap. The slots are disposed along the sleeve within the process side adjacent to the floating bushing seal assembly. The slurry seal assembly is applicable to devices whereby a fluid is movable between an inlet and an outlet.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/765,565 filed Apr. 3, 2018 which is a National Phase of PCTApplication No. PCT/US2016/012404 filed Jan. 7, 2016 both entitledSlurry Seal Assembly which are incorporated in their entirety herein byreference thereto.

FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

None.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention generally relates to a seal assembly that prevents aslurry from contacting a pair of face seal rings and more particularlyis concerned, for example, with a first face seal ring disposed along asleeve that rotates and translates with a shaft, a second face seal ringalong with a retainer arm disposed in a housing so as to benon-rotatable yet translatable, a floating bushing seal assemblydisposed about an outer circumferential surface of the sleeve adjacentto the face seal rings, and a plurality of slots along a front face ofthe sleeve whereby the slots and the floating bushing seal assemblycooperate to resist flow of the slurry in the direction of seal rings.

2. Background

A variety of pumps are employed to transport a fluid with or withoutabrasive constituents from an inlet end to an outlet end. Exemplaryfluids generally include slurries for which specific examples furtherinclude, but are not limited to, petroleum, petrochemicals,pharmaceuticals, and ore/liquid mixtures.

In one example, a centrifugal pump converts rotational kinetic energy ofa component within the pump to the hydrodynamic energy of a fluid.Specifically, an impeller is rotated by an engine, a turbine, anelectric motor or the like. The impeller interacts with a fluid so as todraw the fluid into the pump at an inlet end, to accelerate the fluid asit traverses the pump, and to discharge the fluid at an outlet end.

A slurry pump is a specific example of a centrifugal pump. Slurry pumpsare often employed in mining and ore processing operations.

Ootsuka et al. describes a slurry seal in U.S. Pat. No. 5,195,755 issuedMar. 23, 1993. As illustrated in FIG. 1, the seal includes a stationaryseal ring 3 contacting a first packing 2 that further contacts a flange1 along a pump casing and a rotary seal ring 8 contacting a secondpacking 7 that further contacts a sleeve cover 6 secured to a sleeve 5.The sleeve 5 is attached to the outer surface of a shaft 4. Each sealring 3, 8 includes a sealing surface 3 a, 8 a, respectively, mutuallyarranged to form a seal that resists leakage of a slurry between aslurry side 18 and an atmosphere side 19.

It is well known within the art that the abrasive constituents within aslurry prematurely wear the sealing surfaces 3 a, 8 a. The end resultsare reduced seal performance, reduced seal life, leakage across thesealing surfaces 3 a, 8 a, and contamination outside of the slurry side18. It is not uncommon for slurry seals to fail after only three monthsof ordinary use.

The related art attempts to prevent a slurry from reaching andcontacting the seal rings 3, 8 via a fixed bushing seal assembly 10.FIGS. 2 and 3 separately illustrate a fixed bushing seal assembly 10including a bushing arm 11 that extends from the flange 1 in thedirection of the slurry side 18. A wear layer 12 as shown in FIG. 2 or awindback 15 as shown in FIG. 3 is fixed to and extends from the bushingarm 11 in the direction of the sleeve cover 6 and the sleeve 5. A radialgap 16 is provided between the wear layer 12 and sleeve cover 6 or thewindback 15 and sleeve cover 6 so as to minimize wear to and heating ofthe elements. A fluid, typically water, is pumped into an intermediatechamber 17 after which the fluid is communicated to and across the gap16 and into the slurry side 18. The velocity and pressure of the fluidtraversing the gap 16 must be sufficient to prevent a slurry,originating in the slurry side 18, from reaching the seal rings 3, 8 bycrossing the gap 16 in the direction opposite to that of the fluid flow.

It is well known within the art that the wear layer 12 or the windback15 must be separated from the sleeve cover 6 by a large radial gap orclearance in order to accommodate thermal expansion of and vibrations bycomponents within the seal assembly.

The design envelope of a gap within a fixed bushing seal assembly 10 isinherently problematic because the mass flow rate of a fluid required toproperly resist the counter flow by a slurry increases correspondinglywith gap size. Specifically, the quantity of fluid required for adequatesealing functionality across the gap within a fixed bushing sealassembly is unsustainable in remote or arid locations or impracticalbecause it adversely alters the composition of the slurry within theslurry side.

In view of the mass flow considerations, it is often impossible to sizea gap to properly accommodate the full range of thermal and vibrationconditions within a pump. This means that contact between a fixedbushing seal assembly and a sleeve is inevitable. The rigid nature of afixed bushing seal assembly increases the likelihood of significantdamage to the seal assembly when contact occurs.

Furthermore, in view of the mass flow considerations, it is oftenimpossible to consistently achieve the mass flow rate required toadequately counter the upstream flow of a slurry across a large gap.

Therefore, presently know sealing assemblies are deficient in that thepaired arrangement of face seals is inadequate to prevent leakage of aslurry from a variety of pumps.

Therefore, presently know sealing assemblies are deficient in that fixedbushing seal assemblies impose mass flow rates which are oftenunsustainable, impractical, or impossible.

Therefore, presently know sealing assemblies are deficient in that fixedbushing seal assemblies are susceptible to heat-induced events and/orvibration-induced events that damage components required to prevent aslurry from reaching and contacting the primary sealing elementstherein.

Accordingly, what is required is a seal assembly that avoidsheat-induced and/or vibration-induced excursions that damage a sealassembly.

Accordingly, what is required is a seal assembly that better utilizesflow of a fluid to prevent a slurry from contacting the primary sealingelements therein.

Accordingly, what is required is a seal assembly that utilizes means tosupplement or to enhance flow of a fluid to prevent a slurry fromcontacting the primary sealing elements therein.

SUMMARY OF THE INVENTION

An object of the invention is to provide a seal assembly that avoidsheat-induced and/or vibration-induced excursions that damage a sealassembly.

An object of the invention is to provide a seal assembly that betterutilizes flow of a fluid to prevent a slurry from contacting the primarysealing elements therein.

An object of the invention is to provide a seal assembly that utilizesmeans to supplement or to enhance flow of a fluid to prevent a slurryfrom contacting the primary sealing elements therein.

In accordance with embodiments of the invention, the slurry sealassembly includes a sleeve, a rotatable seal ring, a stationary sealring, and a floating bushing seal assembly. The sleeve is disposedabout, contacts, and is rotatable with the rotatable shaft. Therotatable seal ring contacts and is rotatable with the sleeve. Thestationary seal ring is arranged to form a sealing interface with therotatable seal ring. The floating bushing seal assembly includes abushing arm, an inner ring, an outer ring, an annular space, and a gap.The outer ring is disposed about and contacts the inner ring. Theannular space is disposed between the outer ring and the bushing arm.The floating bushing seal assembly is disposed about the sleeve with thegap disposed between the inner ring and the sleeve. The gap and theannular space permit radial translation of the inner ring and the outerring within the floating bushing seal assembly between the sleeve andthe bushing arm.

In accordance with other embodiments of the invention, a plurality ofslots is disposed along a front face of the sleeve at the process sideand adjacent to the floating bushing seal assembly. Each slot isdisposed along both the front face of the sleeve and an outer annularsurface of the sleeve. The plurality of slots are rotatable with thesleeve.

In accordance with other embodiments of the invention, the plurality ofslots and the inner ring cooperate to resist flow of a slurry along thegap in direction of the rotatable seal ring and the stationary sealring.

In accordance with other embodiments of the invention, the plurality ofslots extends along the outer annular surface into the gap.

In accordance with other embodiments of the invention, a chamferoverlays the plurality of slots.

In accordance with other embodiments of the invention, a windage isdisposed adjacent to the outer annular surface as the plurality of slotsrotates. The windage intersects the gap.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots interacts with the slurry to redirect the slurryaway from the gap.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots produces a windage to redirect the slurry awayfrom the gap.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots interacts with a fluid to redirect the slurryaway from the gap.

In accordance with other embodiments of the invention, an anti-rotationpin extends from the outer ring and engages a slot along the bushingarm.

In accordance with other embodiments of the invention, a pump has theslurry seal assembly.

In accordance with other embodiments of the invention, a fluid traversesthe gap in direction of the process side.

In accordance with other embodiments of the invention, the fluidprevents a slurry from traversing the gap in direction of the atmosphereside.

In accordance with embodiments of the invention, a method of sealing aprocess side from an atmosphere side within a pump includes the steps ofrotating and communicating. A rotatable seal ring and a sleeve arerotated with respect to a stationary seal ring. The rotatable seal ringand the stationary seal ring define a sealing interface therebetween.The rotatable seal ring contacts the sleeve. A fluid is communicatedalong a gap between an inner ring of a floating bushing seal assemblyand the sleeve. An outer ring of the floating bushing seal assembly isdisposed about and contacts the inner ring. An annular space is disposedbetween the outer ring and a bushing arm of the floating bushing sealassembly. The gap and the annular space permit radial movement of theinner ring and the outer ring between the sleeve and the bushing arm.

In accordance with other embodiments of the invention, a plurality ofslots is disposed along a front face of and rotatable with the sleevewithin the process side. The sleeve is disposed about and contacts arotatable shaft. Each slot is disposed along both the front face of thesleeve and an outer annular surface of the sleeve. The inner ring andthe gap are disposed about the outer annular surface of the sleeve.

In accordance with other embodiments of the invention, the plurality ofslots and the floating bushing seal assembly cooperate to resist flow ofa slurry in the direction of the rotatable seal ring and the stationaryseal ring.

In accordance with other embodiments of the invention, communicating androtating steps prevent a slurry originating from the process side fromtraversing the gap toward the atmosphere side.

In accordance with other embodiments of the invention, communicating androtating steps cause the fluid and the plurality of slots to interact soas to redirect a slurry away from the gap.

In accordance with other embodiments of the invention, communicating androtating steps cause the plurality of slots to physically contact aslurry so as to redirect the slurry away from the gap.

In accordance with other embodiments of the invention, the rotating stepcauses a windage about the plurality of slots which redirects a slurryaway from the gap.

In accordance with other embodiments of the invention, communicating androtating steps cause the fluid to be redirected after the fluid entersthe process side.

In accordance with other embodiments of the invention, the fluidinteracts with a slurry so as to redirect the fluid away from the gap.

In accordance with other embodiments of the invention, the rotating stepcauses the plurality of slots to physically interact with and disperse aslurry.

In accordance with other embodiments of the invention, communicating androtating steps accelerate the fluid via the plurality of slots after thefluid enters the process side.

In accordance with other embodiments of the invention, communicating androtating steps accelerate the fluid via the plurality of slots as thefluid traverses the gap.

In accordance with other embodiments of the invention, communicating androtating steps disperse the fluid via the plurality of slots after thefluid enters the process side.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots interacts with the fluid to redirect a slurryaway from the gap.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots physically contacts a slurry to redirect theslurry away from the gap.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots produces a windage to redirect a slurry away fromthe gap.

In accordance with other embodiments of the invention, the fluid isredirected via at least one of the plurality of slots after the fluidenters the process side.

In accordance with other embodiments of the invention, the fluidinteracts with a slurry to redirect the slurry away from the gap.

In accordance with other embodiments of the invention, at least one ofthe plurality of slots physically interacts with and disperses a slurry.

In accordance with other embodiments of the invention, the fluid isaccelerated via at least one of the plurality of slots after the fluidenters the process side.

In accordance with other embodiments of the invention, the fluid isaccelerated via at least one of the plurality of slots as the fluidtraverses the gap.

In accordance with other embodiments of the invention, the fluid isdispersed via at least one of the plurality of slots after the fluidenters the process side.

In accordance with other embodiments of the invention, the fluidprevents a slurry originating from the process side from traversing thegap toward the atmosphere side.

In accordance with other embodiments of the invention, a slurry isredirected away from the gap.

Several exemplary advantages are notable. The invention facilitates asmaller, more controllable gap thereby reducing the mass flow rate andthe total quantity of water required to prevent a slurry from enteringand traversing a gap between a floating bushing seal assembly and asleeve in the direction of an atmosphere side. The invention facilitatesa smaller gap between a floating bushing seal assembly and a sleeveenabling a higher flow velocity by a fluid along the gap therebyimproving resistance to the upstream flow by a slurry. The inventionincludes slots rotatable within the process side that resist upstreamflow of a slurry by physically interacting with the slurry so that theslurry is slung away from a gap between a floating bushing seal assemblyand a sleeve, by generating windage that blocks passage of the slurryinto the gap, by physically separating the slurry into smaller masses sothat the slurry is more easily pushed away from and out of the gap,and/or by enhancing the flow and/or dispersal of the fluid traversingthe gap. The invention avoids slurry-induced damage to the sealingcomponents that directly contact the rotatable seal ring, stationaryseal ring, and retainer arm. The invention is adaptable to cartridge andretrofit forms compatible with conventional pump designs. The inventionimproves seal performance and increases seal life.

The above and other objectives, features, and advantages of thepreferred embodiments of the invention will become apparent from thefollowing description read in connection with the accompanying drawings,in which like reference numerals designate the same or similar elements.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional aspects, features, and advantages of the invention will beunderstood and will become more readily apparent when the invention isconsidered in the light of the following description made in conjunctionwith the accompanying drawings.

FIG. 1 is a partial cross section view illustrating a slurry sealincluding a rotatable face seal and a stationary face seal disposedabout a rotatable shaft (seal and shaft components below centerline notshown) and arranged to provide a seal between a slurry side and anatmosphere side as described by Ootsuka et al. in U.S. Pat. No.5,195,755.

FIG. 2 is an enlarged cross section view illustrating a conventionalfixed bushing seal assembly at one end of a slurry seal wherein thebushing includes a wear layer adjacent to a sleeve cover.

FIG. 3 is an enlarged cross section view illustrating a conventionalfixed bushing seal assembly at one end of a slurry seal wherein thebushing includes a windback adjacent to a sleeve cover.

FIG. 4 is a partial cross section view illustrating a slurry sealdisposed about a rotatable shaft and including a pair of face seal ringsarranged to form a sealing interface, a floating bushing seal assemblydisposed at one end of the slurry seal, and a plurality of slotsdisposed along a sleeve face whereby the floating bushing seal assemblyand the slots cooperate to avoid a slurry from contacting the face sealrings in accordance with an embodiment of the invention.

FIG. 5 is an enlarged cross section view illustrating a floating bushingseal assembly including an inner ring, an outer ring, and an annularspace at one end of a bushing arm attached to a casing in accordancewith an embodiment of the invention.

FIG. 6 is a schematic diagram illustrating the plane (x-y axes) whereinan inner ring and an outer ring within a floating bushing seal assemblymove radially inward and outward perpendicular to a rotational axis(z-axis) in accordance with an embodiment of the invention.

FIG. 7 is a plan view illustrating a plurality of elongated slotsdisposed along a sleeve face in accordance with an embodiment of theinvention.

FIG. 8 is a plan view illustrating a plurality of semi-circular slotsdisposed along a sleeve face in accordance with an embodiment of theinvention.

FIG. 9 is an enlarged cross section view illustrating a shoulder and abase within a slot in accordance with an embodiment of the invention.

FIG. 10 is a schematic diagram illustrating physical interaction withina process side between a slot along a rotating sleeve and a slurrywhereby the slurry is redirected away from a gap between a floatingbushing seal assembly and the sleeve in accordance with an embodiment ofthe invention.

FIG. 11 is a schematic diagram illustrating physical interaction withina process side between a slot along a rotating sleeve and a slurrywhereby the slurry is redirected as several smaller masses away from agap between a floating bushing seal assembly and the sleeve inaccordance with an embodiment of the invention.

FIG. 12 is a schematic diagram illustrating interaction within a processside between a slurry and a barrier formed by windage adjacent to slotsalong a sleeve whereby the slurry is redirected away from a gap betweena floating bushing seal assembly and the sleeve in accordance with anembodiment of the invention.

FIG. 13 is a schematic diagram illustrating interaction within a processside between a fluid exiting a gap between a floating bushing sealassembly and a sleeve and subsequent interaction between the fluid and aslurry whereby the slurry is redirected away from the gap in accordancewith an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to several embodiments of theinvention illustrated in the accompanying drawings. Wherever possible,same or similar reference numerals are used in the drawings and thedescription to refer to the same or like parts. The drawings are insimplified form and are not to precise scale.

While features of various embodiments are separately described, it isunderstood that two or more such features could be combined to formother embodiments.

In addition to the materials described and/or referenced herein,components comprising the seal assembly may be composed of othermaterials understood in the art and suitable to the application.

For purpose of the present application, the term “slurry” is understoodto include liquids with or without particulates capable of prematurelywearing the sealing interface between a pair of face seals. Exemplaryslurries include, but are not limited to, liquids with particulates andliquids without particulates wherein the liquids may be corrosive orotherwise capable of compromising a sealing interface.

Referring now to FIG. 4, a slurry seal assembly 20 is shown disposedabout a rotatable shaft 21 between a process side 54 and an atmosphereside 55. The shaft 21 is a cylindrical structure attached to a means(not shown) that enables the shaft 21 to rotate about a rotation axis 56passing through the lengthwise axis of the shaft 21. Rotation may beeither clockwise or counter clockwise as required and suitable for theapplication. The shaft 21 may be attached to or communicable with amotor or other drive means (not shown) at the atmosphere side 55. Theshaft 21 also may be attached to a component facilitating transport of aslurry between input and output ends at the process side 54. In oneexample, the slurry seal assembly 20 could be disposed along a shaft 21within a slurry pump whereby the shaft 21 is attached at the atmosphereside 55 to an electric or gas-powered motor internal or external to thepump and at the process side 54 to an impeller.

Referring again to FIG. 4, a sleeve 22 includes a radial extension 78and a cylindrical section 79 arranged to form a generally L-shaped crosssection adjacent to a shaft 21. The sleeve 22 is disposed about theshaft 21 so as to contact a portion of the outer surface of the shaft 21defining an interface 74. In some embodiments, the inner diameter of thesleeve 22 and the outer diameter of the shaft 21 are dimensioned so thatthe sleeve 22 slidably engages the shaft 21. In other embodiments, theinner and outer diameters provide an interference fit requiring thesleeve 22 to be heated and/or the shaft 21 cooled for proper assembly.One or more O-rings 49 may be required along the interface 74 to preventmaterial within the process side 54 from traversing the interface 74 inthe direction of the atmosphere side 55.

Referring again to FIG. 4, the sleeve 22 contacts a drive collar 39disposed about the shaft 21 at the atmosphere side 55. The drive collar39 is a ring-shaped element that slidably engages the outer diameter ofthe shaft 21. The drive collar 39 includes two or more set screws 40separately disposed about and aligned radially with respect to thesleeve 22. Each set screw 40 resides within a threaded hole 75 thattraverses the drive collar 39 perpendicular to the shaft 21. The setscrew 40 is rotatable within the threaded hole 75 so that the end of theset screw 40 adjacent to the shaft 21 either engages the shaft 21thereby securing the drive collar 39 to the shaft 21 or disengages theshaft 21 thereby releasing the drive collar 39 from the shaft 21. Thedrive collar 39 includes an annular notch 76 adjacent to the shaft 21that permits the sleeve 22 to slide into and engage the drive collar 39adjacent to the outer diameter of the shaft 21. A plurality of holes 77along the sleeve 22 separately aligns with each threaded hole 75 so thatthe set screws 40 properly contact and engage the shaft 21 to secureboth the drive collar 39 and sleeve 22 to the shaft 21. This arrangementallows the sleeve 22 to rotate with the shaft 21. The drive collar 39 isplaced onto and secured to the shaft 21 and sleeve 22 after othercomponents described herein are assembled onto the sleeve 22. Assemblyof the sleeve 22 and related components may occur either before or afterplacement of the sleeve 22 onto the shaft 21.

Referring again to FIG. 4, a rotatable seal ring 23 encircles the sleeve22 opposite of the shaft 21. The seal ring 23 rotates about the shaft21. The seal ring 23 moves axially with the sleeve 22 during shaft 21movement and radially during shaft 21 vibration. The rotatable seal ring23 is composed of wear and temperature resistant material, examplesincluding, but not limited to, ceramics such as silicon carbide andtungsten carbide. The rotatable seal ring 23 is positioned at theprocess side 54 so as to abut the radial extension 78. An O-ring 27 isprovided between the rotatable seal ring 23 and the radial extension 78to seal an inner chamber 48 from an outer chamber 45. The O-ring 27 maybe a static sealing ring or the like. One or more anti-rotation pins 26are secured to the radial extension 78 and separately extend into a likenumber of comparably dimensioned cavities along the rotatable seal ring23. The anti-rotation pin(s) 26 ensure(s) that the rotatable seal ring23 rotates with the sleeve 22 and shaft 21.

Referring again to FIG. 4, a stationary seal ring 24 also encircles thesleeve 22 opposite of the shaft 21. The seal ring 24 is stationary inthat it does not rotate about the shaft 21; however, the seal ring 24may translate axially with the retainer arm 30. The stationary seal ring24 is also composed of wear and temperature resistant material, examplesincluding, but not limited to, ceramics such as silicon carbide andtungsten carbide. The stationary seal ring 24 is positioned to abut therotatable seal ring 23 along a sealing interface 25. The sealinginterface 25 permits the rotatable seal ring 23 to rotate with respectto the stationary seal ring 24 while maintaining sealing contact betweenthe seal rings 23, 24. The sealing interface 25 further seals an innerchamber 48 from an outer chamber 45. The stationary seal ring 24 abuts aring-shaped retainer arm 30. An O-ring 29 is provided between thestationary seal ring 24 and the retainer arm 30 to seal the innerchamber 48 from the outer chamber 45. The O-ring 29 may be a staticsealing ring or the like. One or more anti-rotation pins 28 are securedto the retainer arm 30 and separately extend into a like number ofcomparably dimensioned cavities along the stationary seal ring 24. Theanti-rotation pin(s) 28 ensure(s) that the stationary seal ring 24remains non-rotatably fixed to the retainer arm 30.

Referring again to FIG. 4, an O-ring 34 is disposed between and contactsthe retainer arm 30 and a gland 31. The retainer arm 30 and gland 31 donot contact so as to allow the retainer arm 30 with stationary seal ring24 to move axially along the length of the shaft 21. The O-ring 34 maybe any sealing device suitable to an interface along which relativemotion is possible. The location of the O-ring 34 between the retainerarm 30 and the gland 31 further seals the inner chamber 48 from theouter chamber 45. In preferred embodiments, the O-ring 34 is placed atthe balanced diameter of the stationary seal ring 24 and the retainerarm 30. The retainer arm 30 is secured to the gland 31 via a pluralityof pins 33 separately disposed about the sleeve 22. Each pin 33 extendsthrough the gland 31 and partially extends into the retainer arm 30. Thepins 33 prevent rotation of the stationary seal ring 24 and retainer arm30 that could otherwise occur due to frictional drag forces along thesealing interface 25 between the rotatable seal ring 23 and thestationary seal ring 24.

Referring again to FIG. 4, a plurality of springs 32 are separatelydisposed about the sleeve 22. A first end of each spring 32 contacts thegland 31 and a second end of each spring 32 partially resides within andcontacts the retainer arm 30. The springs 32 are at least partiallycompressed when assembled between the gland 31 and the retainer arm 30so as to communicate a force onto the retainer arm 30 in the directionof the seal rings 23, 24. This arrangement ensures the seating force andpressure balance required to maintain the sealing interface 25 betweenthe seal rings 23, 24. The springs 32 are axially energized, that isinitially compressed, to permit the retainer arm 30 and the stationaryseal ring 24 to move axially so as to maintain the sealing interface 25when the shaft 21 moves.

Referring again to FIG. 4, the gland 31 abuts and is secured to a sealhousing 35 via a plurality of fasteners 41 separately disposed about thesleeve 22. Each fastener 41 extends through the seal housing 35 andpartially extends into the gland 31. The fasteners 41 are threaded andengage complementary threads within the gland 31. A sealing ring 38 isprovided between the inner diameter of the seal housing 35 and the outerdiameter of the sleeve 22 adjacent to the drive collar 39. Exemplarysealing rings 38 include but are not limited to spring-loaded seals,rubberized seals, and lip seals.

Referring again to FIG. 4, setting plates 36 are provided along the sealhousing 35 opposite of the interface with the gland 31. The settingplates 36 allow assembly of the sealing elements and related componentsin cartridge form about the shaft 21. The setting plates 36 also permitan assembler to properly position the stationary seal ring 24 andretainer arm 30 with respect to the rotatable seal ring 23 and to setthe initial operating length of the springs 32 for the seating force andpressure balance required to maintain the sealing interface 25 betweenthe seal rings 23, 24. Although one setting plate 36 is shown in FIG. 4,it is understood that two or more setting plates 36 are appropriate formost applications and are positioned about the face of the seal housing35.

Referring again to FIG. 4, each setting plate 36 overlays acircumferential portion of the sleeve 22. Each setting plate 36 issecured to the seal housing 35 via a fastener 37 which completelytraverses a slot 82 along the setting plate 36 and partially traversesthe seal housing 35. The fastener 37 engages complementary threadswithin the seal housing 35. Each setting plate 36 is movable along theslot 82 toward and away from the sleeve 22. Each setting plate 36engages a groove 53 disposed along the outer surface of the sleeve 22 tosupport the sealing rings 23, 24, retainer arm 30, gland 31, and sealhousing 35 above the sleeve 22 during assembly of the sleeve 22 onto theshaft 21.

Referring again to FIG. 4, the gland 31 contacts and is secured to acasing 42 or other structure within a pump via fasteners or other meansunderstood in the art (not shown). An O-ring 43 is provided along theinterface between gland 31 and casing 42 to seal the process side 54from the atmosphere side 55. The O-ring 43 may be anytemperature-resistant sealing element suitable for use within a slurryenvironment, examples including but not limited to sealing rings andgaskets. The seal rings 23, 24, retainer arm 30, gland 31, and sealhousing 35 are properly supported by the casing 42 after the gland 31 issecured to the casing 42. This arrangement allows the fasteners 37 to beloosened and the setting plates 36 retracted from the groove 53 therebyseparating the setting plates 36 from the sleeve 22. The fasteners 37are then retightened to secure the setting plates 36 to the seal housing35. It is likewise possible that the fasteners 37 and setting plates 36are removed so as to ensure proper balance by the slurry seal assembly20 about the shaft 21 after the slurry seal assembly 20 is secured tothe casing 42. It is understood that the setting plates 36 must notcontact the sleeve 22 during operation of a pump or the like so that theshaft 21, sleeve 22, rotatable seal ring 23, and O-ring 27 are freelyrotatable with respect to other components comprising the slurry sealassembly 20. The setting plates 36 may be reseated within the groove 53and secured to the seal housing 35 via the fasteners 37 when the slurryseal assembly 20 is repaired or replaced in part or whole.

Referring again to FIG. 4, a floating bushing seal assembly 50 isfastened to and extends from the gland 31 in the direction of theprocess side 54. The floating bushing seal assembly 50 includes anannular bushing arm 57 substantially parallel to the cylindrical section79. The seal rings 23, 24 are interposed between the bushing arm 57 andthe cylindrical section 79. The sealing end of the floating bushing sealassembly 50 is positioned above the radial extension 78 adjacent to theseal rings 23, 24. The seal rings 23, 24 are further interposed betweena grease-filled inner chamber 48 and a water-filled outer chamber 45.

Referring again to FIG. 4, the annular outer chamber 45 is generallydefined by the floating bushing seal assembly 50, gland 31, retainer arm30, seal rings 23, 24, and radial extension 78. A fluid inlet channel 44is provided through the gland 31. The fluid inlet channel 44communicates at one end with the atmosphere side 55 and at another endwith the outer chamber 45. The fluid inlet channel 44 furthercommunicates with a water supply pump (not shown) at the atmosphere side55 to fill the outer chamber 45 with water. The pump replenishes fluidthat otherwise flows from the outer chamber 45 into the process side 54as described herein. In preferred embodiments, the water pressure isslightly higher than the pressure within the process side 54 so as toresist upstream flow (from the process side 54 to the atmosphere side55) by the slurry.

Referring again to FIG. 4, the annular inner chamber 48 is generallydefined by the cylindrical section 79, radial extension 78, seal rings23, 24, retainer arm 30, gland 31, seal housing 35, and sealing ring 38.A grease inlet channel 46 and a grease outlet channel 47 are providedthrough the gland 31. The channels 46, 47 separately communicate at oneend with the atmosphere side 55 and at another end with the innerchamber 48. At least the grease inlet channel 46 further communicateswith a grease unit (not shown) at the atmosphere side 55 which allowsthe inner chamber 48 to be filled with a grease or other viscous,water-insoluble material. The grease unit may be either amanually-actuated or a motor-actuated pump or the like. The greaseoutlet channel 47 permits grease and fluid which traverses the sealinginterface 25 to exit the inner chamber 48. In preferred embodiments, thegrease pressure is slightly higher than the pressure within the processside 54 so as to resist upstream flow (from the process side 54 to theatmosphere side 55) by the slurry.

Referring now to FIGS. 4 and 5, the floating bushing seal assembly 50includes a ring-shaped bushing arm 57 that extends toward the processside 54. In preferred embodiments, the bushing arm 57 is parallel to thecylindrical section 79 as shown in FIG. 4. The bushing arm 57 may besecured to a component within the slurry seal assembly 20 or the devicewithin which the slurry seal assembly 20 is secured. As shown in FIG. 4,an annular bushing arm 57 may be fixed to and extend from the gland 31.The bushing arm 57 may be machined as part of the gland 31 or welded tothe gland 31 or molded onto the gland 31 or mechanically fastened to thegland 31 via a shrink fit. Attachment of the bushing arm 57 to the gland31 or other component within the slurry seal assembly 20 is advantageousto cartridge forms of the assembly 20 whereby the assembly 20 isassembled onto to a shaft 21 as a complete or nearly complete unit. Asshown in FIG. 5, an annular bushing arm 57 may be mechanically fastenedto a casing 42 or the like disposed within a pump. The bushing arm 57may be secured to the casing 42 via a plurality of fasteners 64 disposedabout the sleeve 22. Each fastener 64 could completely traverse a flange83 extending from the bushing arm 57 and partially extend into thecasing 42 thereby engaging complementary threads within the casing 42.Attachment of the bushing arm 57 to the casing 42 or the like isadvantageous to retrofit forms of the slurry seal assembly 20 requiringassembly of the slurry seal assembly 20 within a pump. In otherembodiments, the bushing arm 57 may be press fit onto the casing 42.Regardless of attachment means between bushing arm 57 and casing 42, itmay be advantageous to include an O-ring, gasket, or similar sealingelement (not shown) along the interface the bushing arm 57 and thecasing 42.

Referring again to FIG. 5, an outer ring 58 is disposed about andcontacts an inner ring 59 at one end of the bushing arm 57 adjacent tothe process side 54. The bushing arm 57 includes a generally L-shapedcross section so as to support one lateral side of and to limit radialmovement by the outer and inner rings 58, 59 immediately adjacent to theprocess side 54. A wave spring 61 or the like, examples including butnot limited to compression springs, is provided along a second lateralside of the outer and inner rings 58, 59 opposite of the lateral supportprovided by the bushing arm 57. The wave spring 61 is secured to thebushing arm 57 via a retaining ring 62 securable to a groove 80 alongthe inner diameter of the busing arm 57. The wave spring 61 communicatesa force onto the outer and inner rings 58, 59 in the direction of theprocess side 54. This arrangement ensures a compressive force is appliedonto both outer and inner rings 58, 59 by the wave spring 61 so thatboth rings 58, 59 are biased toward the bushing arm 57 along therotational axis 56. An annular space 60 is provided between the outerdiameter of the outer ring 58 and inner diameter of the bushing arm 57.

Referring again to FIG. 5, at least one anti-rotation pin 63 extendsfrom the outer ring 58 in the direction of the bushing arm 57 andpartially resides within a hole 81 along the outer diameter of the outerring 58. The diameter of the hole 81 is slightly smaller than thediameter of the anti-rotation pin 63 requiring each anti-rotation pin 63to be press fit onto the outer ring 58. The anti-rotation pin 63 shouldbe sufficiently long so as to extend across the annular space 60.

Referring now to FIGS. 5 and 6, at least one slot 88 partially traversesthe inner annular surface of the bushing arm 57. The slot 88 beginsadjacent to the outer chamber 45 and extends in the direction of theprocess side 54. In some embodiments, the slots 88 are parallel to aportion of the radial extension 78, as represented in FIG. 5. In otherembodiments, the slots 88 are parallel to a portion of the radialextension 78 and traverse the outer chamber 45, as represented in FIG.4. The depth and width of each slot 88 should allow a portion of ananti-rotation pin 63 to reside within the slot 88. This arrangementpermits assembly of the outer and inner rings 58, 59 within the bushingarm 57 whereby each anti-rotation pin 63 aligns with and is slidableinto and along one slot 88. The width of the slot 88 should limitrotation of the anti-rotation pin 63 within the slot 88 so as tominimize relative rotational movement between the bushing arm 57 and theouter and inner rings 58, 59.

Referring again to FIGS. 5 and 6, the inner annular surface 66 along theinner ring 59 and the outer annular surface 67 along the radialextension 78 are separated by a gap 65. The gap 65 provides a pathwaybetween the process side 54 and the outer chamber 45 so that fluid mayflow out of the outer chamber 45 in the downstream direction (from theatmosphere side 55 to the process side 54). The distance between theouter annular surface 67 and the inner annular surface 66 generallydefines the height 85 of the gap 65. The height 85 represents theaverage distance between the inner and outer annular surfaces 66, 67when the floating bushing seal assembly 50 is centered about the radialextension 78. While the outer and inner rings 58, 59 may radiallytranslate with respect to the bushing arm 57, pressure forces within thegap 65 minimize variations in the height 85 about the sleeve 22. Inpreferred embodiments, the height 85 is minimized so that the velocityand pressure of the fluid within the gap 65 is sufficient to resistupstream flow by material originating within the process side 54. Thevelocity and pressure conditions required to resist upstream flow areapplication dependent and based on a variety of factors including, butnot limited to, the density, composition and viscosity of the materialwithin the process side 54, the pressure within process side 54, thedensity, viscosity and composition of fluid within the outer chamber 45,and the pressure of the fluid within the outer chamber 45. In onenon-limiting example, a gap 65 with a height 85 of 0.005-inches wassufficient to resist upstream flow when the slurry was bauxite, thepressure within the process side 54 was 190 pounds-per-square-inch, thetemperature within the process side 54 was 200 degrees Fahrenheit, thefluid was water, and the pressure of the fluid within the outer chamber45 was 191 pounds-per-square-inch.

Referring again to FIGS. 5 and 6, the inner ring 59 in preferredembodiments is composed of a hard, temperature resistant, and wearresistant material, examples including, but not limited to, siliconcarbide, tungsten carbide, and high-impact polymers. The outer ring 58is disposed about, contacts, and supports the inner ring 59, therebyfunctioning as a retainer ring. The outer ring 58 may be composed of ametal, examples including, but not limited to, steel and alloys thereof.The outer ring 58 may be shrink fitted onto the inner ring 59.

Referring again to FIGS. 5 and 6, the thermal expansion of the outerring 58 should control expansion of the inner ring 59 so that variationsin the height 85 are minimized over a range of temperatures within theslurry seal assembly 20. For example, a thermal expansion rate of2.5×10⁻⁶ inch/inch/degree Fahrenheit was adequate to control a gap 65with a height 85 of 0.005-inches at an operating temperature of 200degrees Fahrenheit for an inner ring 59 composed of silicon carbide withan inner diameter of 7.377-inches at room temperature, an outer ring 58composed of duplex stainless steel with an inner diameter of7.770-inches at room temperature, and a sleeve 22 composed of duplexstainless steel with a radial extension 78 with an outer diameter of7.362-inches at room temperature. In preferred embodiments, thecoefficients of thermal expansion between the outer ring 58, the radialextension 78, and the shaft 21 are minimized. The combination of thermalproperties and shrink-fit construction permits the outer and inner rings58, 59 to closely match the radial expansion and contraction of thesleeve 22 so that deviations from the design height 85 are minimized,damage to the floating bushing seal assembly 50 and sleeve 22 due tothermal-induced excursions is avoided, and fluid flow is controlled.

Referring again to FIG. 5, the outer annular surface 67 in preferredembodiments is both hard and wear resistant. In some embodiments, theouter diameter of the radial extension 78 may include a thin layer ofhard chrome or other suitable plating. In yet other embodiments, theouter surface of the radial extension 78 may include a ceramic layerapplied thereto via techniques known within the art.

Referring now to FIG. 6, the sleeve 22 is disposed about and contactsthe outer surface of the shaft 21, the outer ring 58 is disposed aboutand contacts the inner ring 59, and the bushing arm 57 is disposed aboutthe outer ring 58. The outer and inner rings 58, 59 are interposedbetween and separate from the bushing arm 57 and sleeve 22 so that theannular space 60 is interposed between the bushing arm 57 and the outerring 58 and so that the gap 65 is interposed between the inner ring 59and the sleeve 22. The annular space 60 and the gap 65 permit the outerand inner rings 58, 59 to float. The float feature allows outward radialmovement 69 and inward radial movement 70 by the outer and inner rings58, 59 within the X-Y plane perpendicular to the Z-axis or rotationalaxis 56. The dynamic flow of fluid and windage across the gap 65 mayresist inward and outward radial excursions by the outer and inner rings58, 59 thereby preferring an arrangement whereby the outer and innerrings 58, 59 are centered about the sleeve 22 and/or re-centered afterthe outer and inner rings 58, 59 are radially displaced off-center.

Referring now to FIGS. 4, 7, 8 and 9, a plurality of slots 52 isprovided along the sleeve 22 within the process side 54. The slots 52are separately disposed along the sleeve face 51 about the circumferenceof the sleeve 22. Each slot 52 is a depression, flute, or recess wherebya base 86 along the slot 52 is disposed below the sleeve face 51. Eachslot 52 is biased toward the outer circumference of the sleeve face 51so that the open ends of the slot 52 are disposed along the sleeve face51 and the outer annular surface 67. In some embodiments, the openingalong the outer annular surface 67 may extend into the gap 65. The outercircumference of the radial extension 78 may include a chamfer 84 or thelike that either does or does not overlay the slots 52.

Referring again to FIGS. 7, 8, and 9, a shoulder 87 is interposedbetween the sleeve face 51 and the base 86 in preferred embodiments.Although the shoulder 87 is shown perpendicular to the base 86 in FIG.9, other arrangements are possible whereby the angle between theshoulder 87 and the base 86 is more or less than ninety degrees (90°).In other embodiments, the base 86 and/or the shoulder(s) 87 may includelinear and/or curved features. The outermost portion of the shoulder 87generally defines the shape of the slot 52 along the sleeve face 51. Insome embodiments, the slots 52 may include a shape that is elongated orcircular as illustrated in FIGS. 7 and 8, respectively; however, othershapes including linear and/or curved features are possible.

The mechanical action by the slots 52 and sealing function by thefloating bushing seal assembly 50 cooperate to resist flow of a slurryupstream toward the rotatable and stationary seal rings 23, 24. Whileseveral such mechanisms that resist flow by a slurry across a slurryseal assembly 20 are separately described herein, it is understood thatsuch mechanisms may separately or jointly prevent a slurry from enteringand/or traversing a gap 65 between a stationary floating bushing sealassembly 50 and a sleeve 22.

Referring now to FIGS. 10 and 11, the slots 52 rotate with the sleeve 22relative to the floating bushing seal assembly 50. A fluid 73 traversesthe gap 65 in a direction away from the seal rings 23, 24. The slots 52may physically interact with a slurry mass (not shown) residing withinthe process side 54. This interaction may tear, chop, or otherwiseseparate portions of the slurry 71 from the slurry mass. A portion ofthe slurry 71 is then captured by a slot 52 and rotates with the sleeve22. Centrifugal forces are communicated to the slurry 71 by the sleeve22 causing the slurry 71 to separate from the slot 52 along a vectordirected outward in a substantially radial direction and away from thefloating bushing seal assembly 50. The result is a redirection of theslurry 71 away from the gap 65. The slurry 71 may be redirected eitheras a single mass as illustrated in FIG. 10 or as two or more smallermasses when the slurry 71 is further dispersed radially outward asillustrated in FIG. 11.

Referring now to FIGS. 7 and 12, the slots 52 rotate with the sleeve 22relative to the floating bushing seal assembly 50. A fluid 73 traversesthe gap 65 in a direction away from the seal rings 23, 24. The slots 52may interact with one or more fluids within the process side 54. Theinteraction may produce a windage 68 in the rotational directionadjacent to the sleeve face 51 and/or the outer annular surface 67, aspresented in FIG. 7. For example, the windage 68 may be characterized asa circular flow of air and/or water within a flow field along and/ornear the outer surface(s) of the sleeve 22. Depending on conditionswithin the flow field, the windage 68 may form a barrier 72 that resistsupstream flow by the slurry 71, thereby redirecting the slurry 71 awayfrom the floating bushing seal assembly 50 and the gap 65 therein.

Referring now to FIG. 13, the slots 52 rotate with the sleeve 22relative to the floating bushing seal assembly 50. A fluid 73 traversesthe gap 65 in a direction away from the seal rings 23, 24. Flowconditions within the fluid 73 generally resist upstream flow of theslurry 71 along the gap 65. Rotation of the slots 52 may allow the slots52 to interact with the fluid 73 and alter the flow characteristicsthereof. In one example, the slots 52 may interact with the fluid 73either physically or via windage 68 so as to increase the velocity ofthe fluid 73 within the gap 65 and/or the process side 54. In anotherexample, the slots 52 may interact with the fluid 73 either physicallyor via windage 68 so as to dispense the fluid 73 more widely within theprocess side 54 than otherwise permitted by the gap 65 alone. Theaccelerated and/or more widely dispersed fluid 73 then may interact withthe slurry 71 within the gap 65 and/or the process side 54 to redirectthe slurry 71 away from the floating bushing seal assembly 50 and thegap 65 therein.

Referring again to FIG. 4, the shaft 21 rotates the sleeve 22 attachedthereto which in turn rotates the rotatable seal ring 23. The rotatableseal ring 23 is disposed adjacent to the stationary seal ring 24 andarranged to form the sealing interface 25 therebetween. The stationaryseal ring 24 is not rotatable as it is attached to one or morenon-rotatable components. The fluid originally residing within the outerchamber 45 is communicated into and across the gap 65 interposed betweenthe floating bushing seal assembly 50 and a portion of the sleeve 22.The shaft 21 also rotates the plurality of slots 52 disposed along aportion of the sleeve 22 within the process side 54. The slots 52 andthe floating bushing seal assembly 50 functionally cooperate to resistflow by the slurry into and across the gap 65, thereby preventing theslurry from entering the outer chamber 45 upstream and from traversingthe sealing interface 25 between the rotatable seal ring 23 andstationary seal ring 24. The fluid generally resists the slurry from theprocess side 54 from traversing the gap 65 toward the atmosphere side55. The slots 52 interact with the fluid to accelerate the fluid eitherwithin or during and/or after entering the process side 54 and/or todisperse the fluid after entering the process side 54 so as to redirectslurry away from the gap 65. A higher flow velocity across the gap 65 ismore likely to break up the slurry as it traverses the gap 65. The slots52 may physically contact the slurry and change the flow direction ofthe slurry so that it flows away from the gap 65. The slots 52 mayproduce windage 68 that changes the flow direction of the slurry so thatit flows away from the gap 65.

It is understood that the slots 52 may simultaneously produce two ormore of the functionalities described herein to resist flow in thedirection of an atmosphere side 55 by material originating in a processside 54. For example, one or more such slots 52 may physically interactwith a slurry, one or more such slots 52 may generate windage 68, andone or more such slots 52 interact with a fluid.

The invention may be used within a variety of applications wherein afluid is movable between an inlet and an outlet. One specificnon-limiting example is a slurry pump wherein a seal assembly isrequired about a rotatable shaft to prevent leakage between a processside and an atmosphere side and the seal assembly must resist prematurewear of sealing components by abrasive particles.

The description above indicates that a great degree of flexibility isoffered in terms of the present invention. Although various embodimentshave been described in considerable detail with reference to certainpreferred versions thereof, other versions are possible. Therefore, thespirit and scope of the appended claims should not be limited to thedescription of the preferred versions contained herein.

What is claimed is:
 1. A slurry seal assembly for use about a rotatableshaft between a process side and an atmosphere side comprising: (a) asleeve disposed about, contacting, and rotatable with said rotatableshaft; (b) a rotatable seal ring contacting and rotatable with saidsleeve; (c) a stationary seal ring arranged to form a sealing interfacewith said rotatable seal ring; and (d) a floating bushing seal assemblyincluding a bushing arm, an inner ring, an outer ring, an annular space,and a gap, said outer ring disposed about and contacting said innerring, said annular space disposed between said outer ring and saidbushing arm, said floating bushing seal assembly disposed about saidsleeve with said gap disposed between said inner ring and said sleeve,said gap and said annular space permit radial translation of said innerring and said outer ring within said floating bushing seal assemblybetween said sleeve and said bushing arm.
 2. The slurry seal assembly ofclaim 1, further comprising: (e) a plurality of slots disposed along afront face of said sleeve at said process side and adjacent to saidfloating bushing seal assembly, each said slot disposed along both saidfront face of said sleeve and an outer annular surface of said sleeve,said plurality of slots rotatable with said sleeve.
 3. The slurry sealassembly of claim 2, wherein said plurality of slots and said inner ringcooperate to resist flow of a slurry along said gap in direction of saidrotatable seal ring and said stationary seal ring.
 4. The slurry sealassembly of claim 3, wherein said plurality of slots extends along saidouter annular surface into said gap.
 5. The slurry seal assembly ofclaim 3, wherein a chamfer overlays said plurality of slots.
 6. Theslurry seal assembly of claim 3, wherein a windage disposed adjacent tosaid outer annular surface as said plurality of slots rotates, saidwindage intersects said gap.
 7. The slurry seal assembly of claim 3,wherein at least one of said plurality of slots interacts with saidslurry to redirect said slurry away from said gap.
 8. The slurry sealassembly of claim 3, wherein at least one of said plurality of slotsproduces a windage to redirect said slurry away from said gap.
 9. Theslurry seal assembly of claim 3, wherein at least one of said pluralityof slots interacts with a fluid to redirect said slurry away from saidgap.
 10. The slurry seal assembly of claim 1, further comprising: (e) ananti-rotation pin which extends from said outer ring and engages a slotalong said bushing arm.
 11. The slurry seal assembly of claim 1, whereina pump has said slurry seal assembly according to claim
 1. 12. Theslurry seal assembly of claim 1, wherein a fluid traverses said gap indirection of said process side.
 13. The slurry seal assembly of claim12, wherein said fluid prevents a slurry from traversing said gap indirection of said atmosphere side.
 14. A method of sealing a processside from an atmosphere side within a pump comprising the steps of: (a)rotating a rotatable seal ring and a sleeve with respect to a stationaryseal ring, said rotatable seal ring and said stationary seal ring definea sealing interface therebetween, said rotatable seal ring contacts saidsleeve; and (b) communicating a fluid along a gap between an inner ringof a floating bushing seal assembly and said sleeve, an outer ring ofsaid floating bushing seal assembly disposed about and contacting saidinner ring, an annular space disposed between said outer ring and abushing arm of said floating bushing seal assembly, said gap and saidannular space permit radial movement of said inner ring and said outerring between said sleeve and said bushing arm.
 15. The method of claim14, wherein a plurality of slots disposed along a front face of saidsleeve within said process side, said plurality of slots rotatable withsaid sleeve, said sleeve disposed about and contacts a rotatable shaft,each said slot disposed along both said front face of said sleeve and anouter annular surface of said sleeve, said inner ring and said gapdisposed about said outer annular surface of said sleeve.
 16. The methodof claim 15, wherein said plurality of slots and said floating bushingseal assembly cooperate to resist flow of a slurry in direction of saidrotatable seal ring and said stationary seal ring.
 17. The method ofclaim 15, wherein said communicating step and said rotating step preventa slurry originating from said process side from traversing said gaptoward said atmosphere side.
 18. The method of claim 15, wherein saidcommunicating step and said rotating step cause said fluid and saidplurality of slots to interact so as to redirect a slurry away from saidgap.
 19. The method of claim 15, wherein said communicating step andsaid rotating step cause said plurality of slots to physically contact aslurry so as to redirect said slurry away from said gap.
 20. The methodof claim 15, wherein said rotating step causes a windage about saidplurality of slots which redirects a slurry away from said gap.
 21. Themethod of claim 15, wherein said communicating step and said rotatingstep cause said fluid to be redirected after said fluid enters saidprocess side.
 22. The method of claim 21, wherein said fluid interactswith a slurry so as to redirect said fluid away from said gap.
 23. Themethod of claim 15, wherein said rotating step causes said plurality ofslots to physically interact with and disperse a slurry.
 24. The methodof claim 15, wherein said communicating step and said rotating stepaccelerate said fluid via said plurality of slots after said fluidenters said process side.
 25. The method of claim 15, wherein saidcommunicating step and said rotating step accelerate said fluid via saidplurality of slots as said fluid traverses said gap.
 26. The method ofclaim 15, wherein said communicating step and said rotating stepdisperse said fluid via said plurality of slots after said fluid enterssaid process side.
 27. The method of claim 15, wherein at least one ofsaid plurality of slots interacts with said fluid to redirect a slurryaway from said gap.
 28. The method of claim 15, wherein at least one ofsaid plurality of slots physically contacts a slurry to redirect saidslurry away from said gap.
 29. The method of claim 15, wherein at leastone of said plurality of slots produces windage to redirect a slurryaway from said gap.
 30. The method of claim 15, wherein said fluid isredirected via at least one of said plurality of slots after said fluidenters said process side.
 31. The method of claim 30, wherein said fluidinteracts with a slurry to redirect said slurry away from said gap. 32.The method of claim 15, wherein at least one of said plurality of slotsphysically interacts with and disperses a slurry.
 33. The method ofclaim 15, wherein said fluid is accelerated via at least one of saidplurality of slots after said fluid enters said process side.
 34. Themethod of claim 15, wherein said fluid is accelerated via at least oneof said plurality of slots as said fluid traverses said gap.
 35. Themethod of claim 15, wherein said fluid is dispersed via at least one ofsaid plurality of slots after said fluid enters said process side. 36.The method of claim 14, wherein said fluid prevents a slurry originatingfrom said process side from traversing said gap toward said atmosphereside.
 37. The method of claim 14, wherein a slurry is redirected awayfrom said gap.